Some of the definitions used in 1960 differ from those used in 1950. These changes were made after consultation with users of census data in order to improve the statistics, even though it was recognized that comparability would be affected. The definitions and explanations should be interpreted in the context of the 1960 Censuses, in which data were collected by a combination of self-enumeration, direct interview, and observation, by the enumerator.

The definitions below are consistent with the instructions given to the enumerator. As in all surveys, there were some failures to execute the instructions exactly. Through the forms distributed to households, the respondents were given explanations of some of the questions more uniformly than would have been given in direct interviews. Nevertheless, it was not feasible to give the full instructions to the respondents, and some erroneous replies have undoubtedly gone undetected.

More complete discussions of the definitions of population items are given in 1960 Census of Population, Volume I, Characteristics of the Population, Part 1, United States Summary, and in each of the State parts.

Median

The median is presented in connection with the data on age, years of school completed, and income. It is the value which divides the distribution into two equal parts, one-half of the oases falling below this value and one-half the oases exceeding this value.

A plus (+) or minus (-) sign after the median indicates that the median is above or below that number. For example, a median of $10,000+ for income indicates that the median fell in the interval "$10,000 or more."

The population of Spanish surname in the Southwest is heterogeneous in both its history and ethnic origin. As early as the sixteenth century, the Spanish-American, Spanish-Colonial, or Hispano group, as it is variously called, settled, in what is now the United States. The largest and earliest settlements were in New Mexico, but there were others in the next century in California and Texas. The Spanish-American group thus lived in territory that came under the American flag by the annexation of Texas, the Treaty of Guadalupe Hidalgo, and the Gadsden Purchase. The second major group, generally called Mexican Americans, consists of recent immigrants from Mexico and their descendents. Immigration from Mexico had been relatively light until about 1910; since that time immigration has been fairly steady and at times quite large. Direct immigrants from Spain, the West Indies, and Central and South America have generally been negligible in number. Ethnically, the population of Spanish-American and Mexican descent ranges from Indians to those of unmixed Spanish ancestry, with many persons being of Spanish-Indian ancestry.

Special recognition of the interest in the Spanish-American and Mexican-American population of the United States was first given by the Bureau of the Census through the collection and publication of data on "Mexicans" in the Census of 1930. The interest which gave impetus to the collection of these statistics was stimulated by the heavy immigration from Mexico during the decade of the twenties. In the 1930 Census, not only were persons of Mexican birth and parentage identified, (as they had been in previous censuses), but an attempt was also made to identify as "Mexicans" persons of Spanish-Colonial descent and the small number of grandchildren of Mexican immigrants among native persons of native parentage and to provide statistics on the entire Spanish-American and Mexican-American population. The category "Mexican" in that census was one of the categories of the racial classification. Enumerators were instructed to classify as "Mexican" all persons of Mexican origin who were not definitely white, Negro, Indian, or Japanese.

In the Census of 1940, a question on mother tongue, or language other than English spoken in earliest childhood, was asked of a 5-percent sample of the entire population, and the responses to this question made possible tabulations for persons of Spanish mother tongue in the three nativity and parentage classes - foreign born, native of foreign or mixed parentage, and native of native parentage. Although the statistics on persons of Spanish mother tongue cannot be said to cover exactly the same segment of the population as was covered by the 1930 statistics on "Mexicans," they would seem to, do so to a considerable extent.

In the 1950 and 1960 Censuses, data relating to persons of Spanish-American and Mexican-American origin were obtained by the identification of persons of Spanish surname on the census schedules as part of the general coding operation. This procedure was limited to the five Southwestern States--Texas, Colorado, New Mexico, Arizona, and California-which in 19V0 accounted for more than 80 percent of all persons of Spanish mother tongue. This method of identification has proved to be a relatively efficient and economical means of obtaining the desired statistics. The merits and shortcomings of identification by surname are discussed below.

The identification of Spanish surnames in 1960 was performed as a part of the manual coding operation. The regular coders were given a list of about 7,000 Spanish surnames originally compiled by the Immigration and Naturalization Service.1 They were instructed to classify a name as Spanish only if it appeared on this list. Other names of apparent Spanish origin were referred to specialists who had been instructed on those characteristics of Spanish surnames which differentiate them from surnames in other Romance languages, such as Portuguese, French, and Italian, The procedure used in 1960 was essentially the same as that used in 1950 and employed the same basic list of names with a few additions and deletions to correct for obvious omissions or errors. The major difference in coding of Spanish surnames in 1950 and 1960 was that in 1950 coders were given more extensive training in recognizing characteristics of Spanish surnames, whereas in 1960 coders simply checked all names to the list of surnames. The list of names thus more nearly operationally defines the Spanish-surname population in 1960 than in 1950. The results appear to be comparable.

Although the validity and reliability of the Spanish-surname classification in 1950 and 1960 were probably not as great as they might have been had the classification been made by a committee of experts, the results appear to have been reasonably adequate. It must be recognized that surnames are only correlated with national origins; that certain surnames are common to a number of different languages and hence that a complete dichotomy of Spanish and non-Spanish names is not possible; that surnames Identified with other European nationalities such as, for example, the Irish are found among Latin Americans; and that there has been some Anglicization of initially Spanish surnames. It is believed, however, that the general adequacy of the classification is not invalidated by these limitations. The Spanish surname classification does identify a population with distinctive social and economic characteristics highly correlated with certain national origins. The adequacy of the classification depends finally on the degree to which the purposes for which the classification was made were met.

The objective of the separate identification of "Mexicans" in the 1930 Census, of the compilation of persons of Spanish mother tongue in 19^0, and of the identification of persons of Spanish surname in 1950 and 1960, was considerably more than the mere identification of persons of Mexican birth or parentage already available from the questions on birthplace of the respondent and of his parents. It involves an attempt to identify the third and later generations of such immigrants as well as the descendants of Spanish-Colonial inhabitants of the Southwest.

Bach of the indexes used to identify this group of persons suffers from certain limitations. The seemingly straightforward approach of collecting and tabulating, data on "Mexicans" encounters the difficulty that in areas in which descendents of the Spanish-Colonial population is concentrated neither respondents nor enumerators regard persons of this type as "Mexican," and thus in such areas there was a gross undercount of this group in the 1930 Census, which is reflected in the figures for native persons.

This situation is most clearly illustrated in the figures for New Mexico, the State In which the great majority of Spanish-Americans are descendents of persons living in the territory prior to its acquisition by the United States. In 1930, the number of persons born in Mexico was about 16,000; by 1940, it had decreased to about 9,000. In 1930, about 43,000 native, persons classified as "Mexican" were enumerated, but, in 1940, about 214,000 native persons of Spanish mother tongue. Since there was no great influx of Spanish-speaking peoples into the State during the decade, it is reasonable to assume that the figures refer to the same segment of the population, and since it is impossible that natural increase could account for a fivefold increase in number, it may be concluded that the question on mother tongue provided a more complete count of the segment of the population under consideration than did identification of "Mexicans" (table A).

Likewise, although the question on mother tongue used in the 1940 Census made possible the classification of native persons of native parentage by mother tongue, it permitted the reporting of English as the language spoken in the home in earliest childhood in homes of persons whose language in their country of origin was in all probability a language other than English. For example, for the United States as a whole, about 7 percent of the native population of Mexican parentage reported English as their mother tongue. Thus for the second and later generations, statistics on mother tongue tend to understate the full extent of foreign origin. This difficulty is illustrated in the figures for California which show an 82-percent Increase from the Spanish mother-tongue total of 19^0 to the Spanish-surname total of 1950. In New Mexico, where Spanish is established on an equal footing with English, this limitation is probably of no great significance. The successive figures for New Mexico for 1940 (based on Spanish mother tongue) and for 1950 and 1960 (based on Spanish surname) seem to reflect a growth that is consistent with the probable natural increase and net migration for the group.

Some interest attaches to the extent to which the population of Spanish surname is of Spanish-American and Mexican-American descent, and conversely, the extent to which the population of Spanish-American and Mexican-American descent is of Spanish surname. Evidence on this point for 1960 and 1950 is available only for the foreign born, and it thus excludes persons of Spanish-Colonial descent. This evidence appears in table B, which presents figures for the foreign born of Mexican birth and of Spanish surname, for the foreign born of Spanish surname but not of Mexican birth, and for the foreign born of Mexican birth but not of Spanish surname, for 1960 and 1950.

Table A. Spanish-American and Mexican-American Population of Five Southwestern States As Variously Indentified In Censuses of 1930 To 1960

Of the total of these three groups In 1960, about 83 percent were persons of both Spanish surname and Mexican birth. This figure represents a slight decline from the comparable value of 86 percent in 1950 for the five States. The decline is attributable to the decrease in California in the proportion of persons of Spanish surname of Mexican birth in the total for that State. There has been a substantial increase in California in the number of persons from other Central and South American countries, most of whom have Spanish surnames. In the other four States, the proportion of persons of Mexican birth with Spanish surname was greater in 1960 than in 1950. Similarly, for all five States, the number of persons of Mexican birth with Spanish surname represented a greater percent of the total number of white persons of Mexican birth in 1960 than in 1950. It would seem from these facts that the coverage of the Spanish-surname coding in 1960 was better than that in 1950.

The number of foreign-born- persons with Spanish surname but not of Mexican origin is of some interest, since it appears to be closely associated with the number of foreign-born persons in the State from countries other than Mexico whose surnames could easily be Spanish or could be confused with Spanish names. Appendix table A-1 presents statistics on birthplace and mother tongue of the foreign-born Spanish-surname population. These data indicate that many of the Spanish-surname persons born elsewhere than in Mexico were also of Spanish mother tongue and were, therefore, probably legitimately Included in the Spanish- surname population as operationally defined even though they do not belong in the group that is of main interest, If Spanish-surname persons of Spanish mother tongue born in countries other than Mexico are added to those born in Mexico, the total comprises 93.4 percent of all foreign-born persons of Spanish surname. These facts imply much more consistent coverage of the population and better quality of the data than can be inferred from table B. The numbers of persons born elsewhere than Mexico include foreign-born persons of Spanish surname -whose country of birth was not reported, many of whom may have been born in Mexico.

Besides the inclusion of foreign-born persons of other than Mexican birth, some other groups may have been inadvertently included in the Spanish-surname classification. It is possible that a large proportion of the persons of Puerto Rican birth or parentage living in the five Southwestern States have been included in the native population of native parentage with Spanish surname.

In fact, an analysis in terms of country of origin and Spanish surname is not possible for the native population of native parentage. For this segment of the population, however, it seems reasonable to infer that the correspondence between Spanish surname and Mexican or Spanish-Colonial descent is somewhat less than among the foreign stock. These persons have had the opportunity to marry outside their initial origin groups for a longer period of time than the foreign stock; and, therefore, the gains and losses through intermarriage may be expected to be somewhat larger than among the foreign stock.

In terms of the available evidence, there appears to be no reason for assuming that the use of surname to identify the Spanish-American population is any less adequate than procedures previously used; and, in most respects, its use should have led to a genuine improvement in the quality of the statistics.

In general, the urban population comprises all persons living in urbanized areas and in places of 2,500 inhabitants or more outside urbanized areas. More specifically, according to the definition adopted for use in the 1960 Census, the urban population comprises all persons living in (a) places of 2,500 inhabitants or more incorporated as cities, boroughs, villages, and towns (except towns in New England, New York, and Wisconsin); (b) the densely settled urban fringe, whether incorporated or unincorporated, of urbanized areas; (c) towns in New England and townships in New Jersey and Pennsylvania which contain no incorporated municipalities as subdivisions and have either 25,000 inhabitants or more or a population of 2,500 to 25,000 and a density of 1,500 persons or more per square mile; (d) counties in States other than the New England States, New Jersey, and Pennsylvania that have no incorporated municipalities within their boundaries and have a density of 1,500 persons or more per square mile; and (e) unincorporated places of 2,500 inhabitants or more. The population not classified as urban constitutes the rural population.

The rural population is subdivided into the rural-farm population, which comprises all rural residents living on farms, and the rural-nonfarm population, which comprises the remaining rural population. In the 1960 Census, the farm population consists of persons living in rural territory on places of 10 or more acres from which sales of farm products amounted to $50 or more in 1959 or on places of less than 10 acres from which sales of farm products amounted to $250 or more in 1959. All persons living in group quarters are classified as nonfarm except the relatively few living in workers' quarters (including quarters for migratory agricultural workers) that are located on a farm or ranch.

Except in New England, an SMSA is a county or group of contiguous counties which contains at least one city of 50,000 inhabitants or more, or "twin cities" with a combined population of at least 50,000. In addition to the county, or counties, containing such a city or cities, contiguous counties are included in an SMSA if, according to certain criteria, they are essentially metropolitan in character and are socially and economically integrated with the central city. In New England, SMSA's consist of towns and cities, rather than counties.

Urban places in 1960 include all incorporated and unincorporated places of 2,500 inhabitants or more, and the towns, townships, and counties classified as urban. Unincorporated places are designated by "U."

The term "color" refers to the division of population into two groups, white and nonwhite. The color group designated as "nonwhite" includes Negroes, American Indians, Japanese, Chinese, Filipinos, Koreans, Hawaiians, Asian Indians, Malayans, Eskimos, Aleuts, etc. Persons of Mexican birth or ancestry who are not definitely of Indian or other nonwhite race are classified as white.

There is some interest in the number of persons of nonwhite races who may have Spanish surnames. In processing the 1960 Census schedules, general, coders classified all persons, regardless of race, as having a Spanish surname or a non-Spanish surname. Appendix table A-2 presents statistics based on a 5-percent sample, which show the racial composition of the Spanish-surname population in Arizona, California, Colorado, New Mexico, and Texas. All other tables in this report contain statistics for the white population only.

This category comprises persons born in the United States, the Commonwealth of Puerto Rico, or a possession of the United States', persons born in a foreign country or at sea who have at least one native American parent; and persons whose place of birth was not reported and whose census report contained no contradictory information, such as an entry of a language spoken prior to coming to the United States.

In the 1960 Census, mother tongue is defined as the principal language spoken in the person's home before he came to the United States. Information on mother tongue, which was obtained, only from foreign- horn persons, was derived from answers to the following question on the Household Questionnaire: "If this person was torn outside the U.S., what language was spoken in his home before he came to the United States?" If a person reported more than one language, the code assigned was the mother tongue reported by the largest number of immigrants from his native country in the 1940 Census.

Residence on April 1, 1955, is the usual place of residence five years prior to enumeration. The category "same house as in 1960" includes all persons 5 years old and over who were reported as living in the same house on the date of enumeration in 1960 and five years prior to enumeration. Included in the group are persons who had never moved during the five years as well as those who had moved but by 1960 had returned to their 1955 residence. The category "different house in the U.S." includes persons who, on April 1, 1955, lived in the United States in a different house from the one they occupied on April 1, 1960. This category was subdivided into three groups according to their 1955 residence, viz., "different house, same county," "different county, same State," and "different State." The category "abroad" was divided into two groups:

"Mexico," comprising those persons whose residence was in Mexico in 1955, and "other," which includes those with residence in another foreign country or an outlying area of the United States in 1955- (In the coding of this item, persons who lived in Alaska or Hawaii in 1955 but in other States in 1960 were classified as living in a different State in 1955.) Persons 5 years old and over who had indicated they had moved into their present residence after April 1, 1955, hut for whom sufficiently complete and consistent information regarding residence on April 1, 1955, was not collected are included in the group "moved, place of residence in 1955 not reported."

School enrollment is shown for persons 5 to 34 years old. Persons were included as enrolled in school if they were reported as attending or enrolled in a "regular" school or college at any time between February 1, 1960, and the time of enumeration. Regular schooling is that which may advance a person toward an elementary school certificate or high school diploma, or a college, university, or professional degree. Schooling that was not obtained in a regular school and schooling from a tutor or through correspondence courses were counted only if the credits obtained were regarded as transferable to a school in the regular school' system. Schooling which is generally regarded as not regular includes that which is given in nursery schools, in specialized vocational, trade, or business schools; in on-the-job training; and through correspondence courses.

The data on years of school completed were derived from the answers to the two questions: (a) "What is the highest grade (or year) of regular school he has ever attended?" and (b) "Did he finish this grade (or year)?" Enumerators were instructed to obtain the approximate equivalent grade in the American school system for persons whose highest grade of attendance was in a foreign school system, whose highest level of attendance was in an ungraded school, whose highest level of schooling was measured by "readers," or whose training by a tutor was regarded as qualifying under the "regular" school definition. Persons were to answer "No" to the second question if they were attending school, had completed only part of a grade before they dropped out, or failed to pass the last grade attended.

The number in each category of highest grade of school completed represents the combination of (a) persons who reported that they had attended the indicated' grade and finished it, and (b) those who had attended the next higher grade but had not finished it.

Elementary school, as defined here, includes grades 1 to 8, and high school includes grades 9 to 12. College includes junior or community colleges, regular 4-year colleges, and graduate or professional schools.

This classification refers to the marital status of the person at the time of enumeration. Persons classified as "married" comprise, therefore, both those who have been married only once and those who remarried after having been widowed or divorced. Persons reported as separated (either legally separated or otherwise absent from the spouse because of marital discord) are classified as a subcategory of married persons. The enumerators were instructed to report persons in common-law marriages as married and persons whose only marriage had been annulled as single. Persons "ever married" are those in the categories married (including separated), widowed, and divorced.

The number of married men may be different from the number of married women for an area because of the absence of husbands or wives from the country, because the husband and wife have different places of residence, because of the methods used to inflate the sample data, or for other reasons.
A married person with "spouse present" is a man or woman whose spouse was enumerated as a member of the same household even though he or she may have been temporarily absent on business or vacation, visiting, in a hospital, etc., at the time of enumeration.

A household consists of all the persons who occupy a housing unit. A house, an apartment or other group of rooms, or a single room, is regarded as. a housing unit when it is occupied or intended for occupancy as separate living quarters; that is, when the occupants do not live and eat with any other persons in the structure and there is either (1) direct access from the outside or through a common hall or (2) a kitchen or cooking equipment for the exclusive use of the occupants. The population per household is obtained by- dividing the population in households by the number of households.

All persons who are not members of households are regarded as living in group quarters. Group quarters are living arrangements for institutional Inmates or for other groups containing five or more persons unrelated to the person in charge. Most of the persons in group quarters live in rooming houses, college dormitories, military barracks, or institutions. Inmates of institutions are persons for whom care or custody is provided in such places as homes for delinquent or dependent children; homes and schools for the mentally or physically handicapped; places providing specialized medical care for persons with mental disorders, tuberculosis, or other chronic disease; nursing and domiciliary homes for the aged and dependent; prisons; and jails.

For persons in households, several categories of relationship to head of household are recognized in this report;

1. The head of the household is the member reported as the head by the household respondent. However, if a married woman living with her husband is reported as the head, her husband is classified as the head for the purpose of census tabulations.
2. The wife of a head of a household is a woman married to and living with a household head. This category includes women in common-law marriages as well as women in formal marriages.
3. An other relative of the head is a person related to the head of the household by blood, marriage, or adoption, but not included specifically in another category.
4. A nonrelative of the head is any member of the household who is not related to the household head. This category includes lodgers (roomers and partners, relatives of such persons, and foster children) and resident employees (maids, hired farm hands, etc.).

A family consists of two or more persons in the same household who are related to each other, by blood, marriage, or adoption; all persons living in one household who are related to each other are regarded as one family. In a primary family, the head of the family is the head of a household. Other families are secondary families. A "husband-wife" family is a family in which the head and his wife are enumerated as members of the same household.

A subfamily is a married couple with or without children, or one parent with one or more own children under 18 years old, living in a housing unit and related to the head of the household or his wife. The number of subfamilies is not included in the count of families.

An own child of a household head or of a family head is defined here as a single (never married) son, daughter, stepchild, or adopted child of the person in question. This report includes data on own children of the family head and on women by presence of own children.

An unrelated individual is (1) a member of a household who is living entirely alone or with one or more persons all of whom are not related to him, or (2) a person living in group quarters who is not an inmate of an institution. A head of a household living alone or with nonrelatives only is a primary individual.

The data on employment status relate to the calendar week prior to the date on which the respondents filled their Household Questionnaires or were interviewed by enumerators. This week is not the same for all respondents because not all persons were enumerated during the same week.

Employed persons comprise all civilians 14 years old and over who were either (a) "at work"-those who did any work for pay or profit, or worked without pay for 15 hours or more on a family farm or in a family business; or (b) were "with a job but not at work"- those who did not work and were not looking for work but had a job or business from which they were temporarily absent because of bad weather, industrial dispute, vacation, illness, or other personal reasons.

Persons are classified as unemployed if they were 14 years old and over and not "at work" but looking for work. A person is considered as looking for work not only if he actually tried to find work but also if he had made such efforts recently (i.e., within the past 60 days) and was awaiting the results of these efforts. Persons waiting to he called back to a job from which they had been laid off or furloughed are also counted as unemployed.

The "civilian labor force" includes all persons classified as employed or unemployed, as described above. The "labor force" also includes members of the Armed Forces (persons on active duty with the United States Army, Air Force, Navy, Marine Corps, or Coast Guard).

Persons "not in the labor force" comprise all those 14 years old and over who are not classified as members of the labor force, including persons doing only incidental unpaid family work (less than 15 hours during the week).

The statistics on hours worked pertain to the number of hours actually worked, and not necessarily to the number usually worked or the scheduled number of hours. For persons working at more than one job, the figures reflect the combined number of hours worked at all jobs during the week. The data on hours worked presented in this report provide a broad classification of persons at work into full-time and part- time workers. Persons are considered to be working full time if they worked 35 hours or more during the reference week and part time if they worked less than 35 hours.

The data on weeks worked in 1959 pertain to the number of different weeks during 1959 in which a person did any work for pay or profit (including paid vacation and sick leave) or worked without pay on a family farm or in a family business. Weeks of active service in the Armed Forces are also included.

The data on occupation and industry in this report are for employed persons and refer to the job held during the week for which employment status was reported. For persons employed at two or more jobs, the data refer to the job at which the person worked the greatest number of hours. The occupation and industry statistics presented here are based on the detailed systems developed for the 1960 Census; see 1960 Census of Population, Classified Index of Occupations and Industries. U.S. Government Printing Office, Washington, D.C., 1960.

Information on income for the calendar year 1959 was requested from all persons 14 years old and over in the sample. "Total income" is the sum of amounts reported separately for wage or salary income, self- employment income, and other income. Wage or salary income is defined as the total money earnings received for work performed as an employee. It represents the amount received before deductions for personal income taxes, Social Security, bond purchases, union dues, etc. Self-employment income is defined as net money income (gross receipts minus operating expenses) from a business, farm, or professional enterprise in which the person was engaged on his own account. "Earnings" are obtained by summing wage or salary income and self- employment income. Other income includes money income received from such sources as net rents, interest, dividends, Social Security benefits, pensions, veterans' payments, unemployment insurance, and public assistance or other governmental payments, and periodic receipts from insurance policies or annuities. Not included as income are money received from the .sale of property (unless the recipient was engaged in the business of selling such property), the value of income "in kind," withdrawals of bank deposits, money borrowed, tax refunds, and gifts and lump-sum inheritances or insurance payments.

In the statistics on family income, the combined incomes of all members of each family are treated as a single amount. Although the time period covered by the income statistics is the calendar year 1959, the composition of families refers to the time of enumeration. For most of the families, however, the income reported was received by persons who were members of the family throughout 1959- The number of earners in the family refers to the number of family members who had wage or salary income or self-employment income.